1. Field of the Invention
The present invention relates generally to fans for moving air. More specifically, the present invention concerns a high performance tubeaxial fan that provides increased efficiency and reduced noise levels relative to prior art tubeaxial fans.
2. Discussion of Prior Art
Fans are used in a variety of household and industrial applications to force air into and/or out of certain environments. For example, many industrial settings utilize ventilation systems that incorporate one or more fans to provide clean air and/or to exhaust polluted air from various work locations. The optimum fan for a particular application will have certain performance criteria required by the application (e.g., flow volume requirements, pressure differentials, etc.).
Tubeaxial fans are known in the art and are particularly suited for applications requiring the movement of large amounts of air with only relatively small pressure differentials (e.g., spray booths, cleaning tanks, mixing rooms, etc.). However, these prior art tubeaxial fans, while effective, have several non-optimizing limitations. For example, prior art tubeaxial fans have a relatively high noise level during operation. High noise levels are undesirable because many applications where tubeaxial fans are utilized involve settings where humans live or work. Furthermore, prior art tubeaxial fans have a relatively low efficiency. Low efficiency is undesirable because many applications where tubeaxial fans are utilized involve extended periods of continuous or repeated fan use.
The present invention provides an improved tubeaxial fan that does not suffer from the limitations of the prior art tubeaxial fans as set forth above. The inventive fan provides a high performance tubeaxial fan that combines both reduced noise levels and improved efficiency relative to the prior art tubeaxial fans.
A first aspect of the present invention concerns a fan that broadly includes a central hub for rotation about a rotational axis, and a plurality of blades fixed relative to the hub to project radially therefrom. Each of the blades presents a root adjacent the hub and a tip spaced radially outward from the root. Each of the tips is spaced from the rotational axis a tip radius. Each of the blades presents a chord length that is smaller at the root and tip relative to a maximum chord length location spaced between the root and tip. The chord length presented by each of the blades progressively and gradually increases from the root to the maximum chord length location and progressively and gradually increases from the tip to the maximum chord length location. Each of the blades presents a stagger angle that is relatively greater at the tip than at the root. The stagger angle presented by each of the blades progressively and gradually increases from the root to the tip. Each of the blades presents a camber height that is smaller at the root and tip relative to a maximum camber height location spaced between the root and tip. The camber height presented by each of the blades progressively and gradually increases from the root to the maximum camber height location and progressively and gradually increases from the tip to the maximum camber height location.
A second aspect of the present invention concerns a fan that broadly includes a propeller housing, and a propeller rotatably supported in the housing for rotation about a rotational axis. The propeller includes a central hub and a plurality of blades fixed relative to the hub to project radially from the hub. Each of the blades includes an external surface having a shape defined by the relative positioning of a plurality of coordinates contained in at least nine cross-sections of the external surface. The plurality of coordinates is defined on a three-dimensional grid having its origin on the rotational axis and including an X axis extending radially from the origin, a Y axis coplanar with the X axis and extending from the origin orthogonally to the X axis, and a Z axis coextensive with the rotational axis. The plurality of coordinates comprises the coordinates listed in TABLE 2 herein.